1. Field of the Invention
The present invention relates generally to automated storage libraries for storing and retrieving computer data, and more particularly to systems and methods for detecting and handling storage devices with an automated gripper and integrated camera in automated storage libraries.
2. Description of the Related Art
A popular device for the handling and storage of large amounts of information in a data processing system includes an automated storage library system. Automated storage library systems generally improve the access speed and reliability of data storage libraries containing large amounts of information. Automated storage library systems typically include a plurality of storage media devices, a transport mechanism, and one or more storage media drives in communication with a computer system or network for inputting and outputting desired information to and from the plurality of storage media devices.
Magnetic tape cartridges, for example, have proven to be an efficient and effective medium for data storage in computer systems and storage libraries. Automated tape cartridge libraries generally have a plurality of storage bins or slots for storing tape cartridges, a robotic picker mechanism (often referred to as a “picker”), and one or more tape drives. The robotic picker may be controlled to select a specific storage tape cartridge from the library and transfer the tape cartridge between a storage slot and a tape drive within seconds. The robotic picker typically includes a gripper or hand mechanism positioned on the robotic picker. The robotic picker may position the gripper near a desired tape cartridge such that the gripper may grip the tape cartridge to remove the tape cartridge from the storage bin and transfer the tape cartridge and load the tape cartridge into a tape drive, load port (for adding or removing tapes from the library), or the like.
An automated storage cartridge library is typically interfaced to a computer system such as a computer network or the like. The storage library or interfaced computer system may index the location of the tape cartridges and their associated stored data within the storage library for later retrieval of the stored information. When desired, the storage library may be activated to retrieve a desired storage tape and load it into a drive to access the stored information and/or write new information. In large storage libraries multiple tape drives are generally employed to improve access and storage performance by operating in parallel as well as providing back-up drives in case of failure, maintenance, and the like.
To quickly locate and retrieve a cartridge from the library an inventory of the storage cartridge tapes located within the storage library system is performed, typically after loading cartridges into the library system. Each cartridge is equipped with a label, such as a barcode label, that may be read by a bar code scanner mechanically coupled to the gripper. The bar code scanner is generally a laser that mechanically scans across the barcode label surface. The bar code label may be used to identify the cartridge, e.g., the contents of stored data (if any) on that particular cartridge.
The ability for the library system to distinguish between unlabeled cartridges and empty storage locations is generally needed so the system may determine an accurate library inventory. One method to achieve this is to place an “empty” barcode label within the storage slot such that when read by a bar code reader it is associated with an empty slot. The “empty” barcode label is blocked from view of the bar code reader when a cartridge is placed within the storage slot. If a barcode label is not detected, however, the system remains uncertain if the storage slot contains a cartridge, e.g., whether the label is missing from the cartridge or the storage slot.
Another typical method for determining if a storage slot is empty includes having the robotically actuated gripper assembly reach into each storage slot and physically sense whether or not a cartridge is present. For example, an actuator current level may be monitored until it rises above a threshold level indicating a cartridge is present. Extending the robotically actuated gripper assembly or other mechanical device into each storage slot for inventory purposes, however, adds significant time to the inventory process and may cause wear or damage to the tape cartridge and/or gripper assembly.
Another method includes an additional sensor (separate from and in addition to a barcode scanner) dedicated to sensing the presence of a cartridge tape in the slot that may be mounted to the gripper assembly in addition to a barcode scanner or the like. Such an example is described in U.S. Pat. No. 6,213,705 and is hereby incorporated by reference in its entirety. An additional sensor on the gripper assembly, however, may add significant cost and complexity to the system as well as time to the inventory process.
Therefore, what is needed is a system and method for reading barcode labels or other indicia associated with storage devices in an automated storage library system with increased speed and reliability. Further, a system and method for sensing the presence (with and without a barcode label) or absence of a storage device within a storage slot of the automated storage library without additional cost and complexity to the system are desired.